This invention relates generally to structural attachment and, more specifically, to structural attachment of fairings.
Ongoing research into aircraft design from time to time may discover improved wing contour designs to improve aircraft performance. Even subtle changes in wing contours may, for example, improve lift-to-drag ratios. Such improvements in lift-to-drag ratios can result in greater aircraft lift capacity or improved fuel economy per unit cargo weight. Certainly, future aircraft can benefit greatly from these enhancements.
Although future aircraft will benefit from such improvements, it would be advantageous to be able to incorporate these design changes in aircraft currently in service. Currently used aircraft have useful lives measured in decades, and such durable assets certainly represent an appreciable investment which owners would like to be able to upgrade. Accordingly, it would be advantageous to incorporate improved wing designs in currently deployed commercial or military aircraft.
Unfortunately, changing wing contours on currently in-service aircraft presents a considerable challenge. Wings on aircraft must be intricately interconnected with their aircraft to allow for flight deck controls to be connected to the many control surfaces that constitute part of the wings. Moreover, other aircraft systems, such as fuel tanks, are integrated into the wings. As a result, it is not very feasible to remove an aircraft wing and replace it with a new and improved wing. On the other hand, wing contours of existing aircraft can be modified in place by applying fairings to a surface of the wing. In particular, a contour of an upper wing surface can be changed by affixing a convex fairing to the upper wing surface.
Problems remain, however, in how to accomplish the attachment of fairings to such wing surfaces practicably, cost effectively, and durably. For example, mounting a fairing to a hollow aircraft wing housing a fuel tank presents all of the above problems. The fairing would have to be anchored to structural members within the wing such as stringers to be durable. At the same time, the fairing has to be attached without puncturing the fuel tanks inside the wing. Drilling or otherwise driving an attachment device through the fairing and into the wing, engaging the stringers, and not puncturing the tank presents a formidable problem. The problem becomes especially daunting if it is to be accomplished cost effectively within a reasonable amount of time and without incurring wasted expenses for repairing damaged wing supports or resealing punctured fuel tanks.
Thus, there is an unmet need in the art for attaching a fairing to an aircraft wing with a method that is durable, cost effective, and practicable to allow in-service aircraft to benefit from improvements in wing contour design.
The present invention provides a practical method for attaching a fairing to a body. The method allows for attach anchors to be inserted into the wing directly, optionally using existing securing orifices used to secure a body surface to the supporting structure of the body. Using existing securing orifices allows the attach anchors to be installed without meticulously drilling of the fairing and the surface of the body in order to connect with a structural member while not puncturing a tank. The fairing can then be mounted over the attach anchors, slid into place, and locked in position, achieving a practical and durable connection of the fairing to the wing.
An exemplary embodiment of the present invention provides a method for attaching a fairing to a body or aircraft wing. A plurality of attach anchors is disposed on the body or aircraft wing to which the fairing is to be attached. Disposed in the fairing is a plurality of core pockets that are alignable with the plurality of attach anchors, and each of the core pockets defines a channel. The fairing is placed over the body or the aircraft wing such that heads of the attach anchors are received in the core pockets. The fairing is then slid across the body or the aircraft wing with the channels sliding along the heads of the attach anchors such that the fairing is prevented from being lifted away from the body or aircraft wing.
Embodiments of the present invention may employ attach anchors shaped to match an inner cross-sectional shape of the channels of the core pockets in the fairing. An attach anchor may be a one piece assembly. Alternatively, an attach anchor may include an interlocking fitting at the head of the attach anchor, where the interlocking fitting is shaped to engage the channel. The interlocking fitting then is secured to the body wing surface with a securing pin mounted through the interlocking fitting. The interlocking fitting may be engaged by the securing pin through a bushing having an eccentric opening, thereby allowing the interlocking fitting to be aligned to match positions of the core pockets in the fairing. The attach anchors may include securing orifices so that locking members can be inserted through the fairing into the securing orifices once the fairing is in place to lock the fairing in position. As desired, a transitioning member can be applied over such a fairing to seal any gaps around the fairing. Embodiments may be used with any bodies that can benefit from a changed shape, including aircraft wings, aircraft bodies, or other shapes as desired for a particular application.